[Controls] Fix left padding in view mode

[Heenawter]

Describe the bug:
Now that we are using compressed styling for controls, the small EuiIcon that we were using to simulate left padding in view mode (see #184533) is too large.

EuiIcon doesn't have an xs option, so we might be forced to just do an empty div with an enforced width of 8px instead (to match the right padding that is now 8px from switching to compressed styling instead of the previous 16px).

Here's what that would look like:

cc @cqliu1 @rshen91

See #192094 (comment) for the discussion around this.

[elasticmachine]

Pinging @elastic/kibana-presentation (Team:Presentation)